It is known that various particulate substances such as organic particulate substances (e.g. thermoplastic resins such as methacrylate and polystyrene which may be crosslinkable, thermosetting resins such as silicone resin) or inorganic particulate substances (e.g. silica, mica, talc, diatomaceous earth, calcium carbonate, silicon oxide, aluminumoxide, titanium oxide, aluminum hydroxide, etc.) are added, as an additive or filler, to a resin composition or paint composition in order to improve the characteristics of molded articles or coating layers. However, when the affinity between such a particulate substance and a resin deteriorates, the mechanical strength of the molded articles or coatings also deteriorates considerably. As a result, the species of a particulate substance is greatly restricted by the species of a resin to be used.
A particulate substance treated with a surface-treating agent has also been used to improve the affinity of the particulate substance. For example, there are known particulate substances such as particulate substances treated with resin, particulate substances treated with surface-treating agent, particulate substances treated with a surfactant, or the like. These particulate substances, however, are not reactive, and give limitation for improvements in mechanical and chemical properties of molded articles or coatings.
In Japanese Patent Application Laid-open No. 184224/1994, there is disclosed a method for producing reactive particles by reacting a polymer having a functional group containing an active hydrogen atom such as carboxyl group at an end or a side chain of a hydrophobic principal chain (e.g. modified olefinic polymers) with an oxazoline. Addition of a small quantity of such reactive particles obtained by this method to polymer compositions mutually incompatible is advantageous for obtaining a polymer alloy. The reactive particles recited in this reference, however, do not function well because of their relatively large particle size and being not containing many active sites.
Accordingly, an object of the present invention is to provide reactive particles each having a number of active sites and the method for producing the same.
An another object of the present invention is to provide reactive particles able to function effectively as a crosslinking agent or carrier even in small quantities.
A further object of the present invention is to provide reactive particles having high activity in spite of their being ultra-fine particulates each having a remarkably small mean particulate size.